Cell Growth and Reproduction in EUKARYOTES

What is a Eukaryotic Cell? Cell that HAS nucleus Contains double stranded DNA Animal and plant cells!!

DNA DNA provides the blueprints or instructions for protein synthesis. Cells cannot survive unless there is enough DNA to support the protein needs of the cell.

Cell Reproduction The cell theory states that “all cells come from pre-existing cells.” Cell division is the process by which this happens! Cell division results in two cells that are identical to the original parent cell. All organisms grow and change; worn out tissues are repaired or replaced by newly produced cells!

Before we learn about division, lets start with the BASICS! What is “Genetic Material”? – DNA Where do we find DNA? – The cell nucleus

So what the heck is a chromosome?! Chromosome- Tightly coiled strands of DNA Where are chromosomes found? – THE NUCLEUS!

Parts of the chromosome Each chromosome has 2 CHROMATIDS Each chromosome has 1 CENTRIOLE holding both Chromatids together

How many chromosomes in a cell!? Humans have 46 total chromosomes 23 pairs of chromosomes

What is MITOSIS? The process of the cell dividing ASEXUALLY Only ONE PARENT is needed One PARENT CELL splits into TWO DAUGHTER CELLS Both daughter cells have IDENTICAL DNA to parent cell

Let’s make like hairs and SPLIT

Phase 1: INTERPHASE Interphase contains 3 stages! 3 stages G1 – Cell grows rapidly and protein production is high S – Cell copies its chromosomes and DNA synthesis occurs G2 – Short growth period in which mitochondria and other organelles are made and parts needed for cell division (centrioles) are manufactured

INTERPHASE

Interphase During this phase, the cell copies its DNA in preparation for the division.

Phase 2: PROPHASE PROPHASE – longest phase of mitosis Chromatin (DNA strands) coil up into visible chromosomes They look kind of hairy! Each chromosome is made of two identical halves called SISTER CHROMATIDS These halves are held together by a CENTROMERE

PROPHASE

PROPHASE CONTINUED… As prophase continues, the nucleus begins to disappear as the nuclear envelope and the nucleolus disintegrate. At this time, the CENTRIOLES begin to migrate to opposite poles of the cell The SPINDLE begins to form between the centrioles. “Chromosomes PREPARE for division”

What the heck is a centriole? A small set of microtubules Contain SPINDLE FIBERS Centrioles are found in pairs and travel in pairs Centrioles travel to opposite poles of the nucleus to begin the divison process

PROPHASE CONTINUED… CENTRIOLES SPINDLE FIBERS

METAPHASE The chromosomes begin to line up on the midline or equator of the spindle The spindle fibers of the centrioles become attracted to the centromeres of chromosomes (middle of chromosomes “Spindle fibers MEET the centromeres”

METAPHASE

ANAPHASE 3) ANAPHASE – Third phase of mitosis Spindle fibers pull the chromosomes Sister chromatids begin to separate Centromeres split apart and the chromatids are pulled apart “Split from Annie”

TELOPHASE Chromatids are pulled to opposite poles of the cell Nucleolus reappears and new nuclear envelope forms around each new set of chromosomes New double membrane begins to form between two new nuclei

TELOPHASE

CYTOKINESIS The cell’s cytoplasm finally divides and the cell starts to pinch along the equator of the cell forming two new cells! “Cytokinesis, division of cytoplasm”

Overview